E16.15 Keynote Inc. uses a calendar year for financial reporting. The company is authorized to issue 20,000,000 shares of $1 par common stock. At no time has Keynote issued any potentially dilutive securities. Listed below is a summary of Keynote's common stock activities. 5,000,000 1,000,000 1. Number of common shares issued and outstanding at December 31, 2018 2. Shares issued for cash on March 31, 2019 3. A 2-for-1 stock split of Keynote's common stock took place on August 31, 2020. 4. Shares issued as a result of a 30% stock dividend on June 30, 2021 3,600,000 Instructions (a) Compute the weighted-average number of common shares used in computing earnings per common share for 2019 on the 2020 comparative income statement. (b) Compute the weighted-average number of common shares used in computing earnings per common share for 2020 on the 2020 comparative income statement. (c) Compute the weighted-average number of common shares to be used in computing earnings per common share for 2020 on the 2021 comparative income statement (d) Compute the weighted-average number of common shares to be used in computing earnings per common share for 2021 on the 2021 comparative income statement. (CMA adapted)